2 * imap.c -- IMAP2bis/IMAP4 protocol methods
4 * Copyright 1997 by Eric S. Raymond
5 * For license terms, see the file COPYING in this directory.
12 #if defined(STDC_HEADERS)
15 #include "fetchmail.h"
21 #endif /* OPIE_ENABLE */
23 #ifndef strstr /* glibc-2.1 declares this as a macro */
24 extern char *strstr(); /* needed on sysV68 R3V7.1. */
27 /* imap_version values */
28 #define IMAP2 -1 /* IMAP2 or IMAP2BIS, RFC1176 */
29 #define IMAP4 0 /* IMAP4 rev 0, RFC1730 */
30 #define IMAP4rev1 1 /* IMAP4 rev 1, RFC2060 */
32 static int count, unseen, deletions = 0;
33 static int expunged, expunge_period, saved_timeout = 0;
34 static int imap_version, preauth;
36 static char capabilities[MSGBUFSIZE+1];
37 static unsigned int *unseen_messages;
39 static int imap_ok(int sock, char *argbuf)
40 /* parse command response */
42 char buf[MSGBUFSIZE+1];
48 if ((ok = gen_recv(sock, buf, sizeof(buf))))
51 /* all tokens in responses are caseblind */
52 for (cp = buf; *cp; cp++)
56 /* interpret untagged status responses */
57 if (strstr(buf, "* CAPABILITY"))
58 strncpy(capabilities, buf + 12, sizeof(capabilities));
59 else if (strstr(buf, "EXISTS"))
63 * Nasty kluge to handle RFC2177 IDLE. If we know we're idling
64 * we can't wait for the tag matching the IDLE; we have to tell the
65 * server the IDLE is finished by shipping back a DONE when we
66 * see an EXISTS. Only after that will a tagged response be
67 * shipped. The idling flag also gets cleared on a timeout.
69 if (stage == STAGE_IDLE)
71 /* we do our own write and report here to disable tagging */
72 SockWrite(sock, "DONE\r\n", 6);
73 if (outlevel >= O_MONITOR)
74 report(stdout, "IMAP> DONE\n");
76 mytimeout = saved_timeout;
80 else if (strstr(buf, "PREAUTH"))
83 * The server may decide to make the mailbox read-only,
84 * which causes fetchmail to go into a endless loop
85 * fetching the same message over and over again.
87 * However, for check_only, we use EXAMINE which will
88 * mark the mailbox read-only as per the RFC.
90 * This checks for the condition and aborts if
91 * the mailbox is read-only.
93 * See RFC 2060 section 6.3.1 (SELECT).
94 * See RFC 2060 section 6.3.2 (EXAMINE).
96 else if (!check_only && strstr(buf, "[READ-ONLY]"))
99 (tag[0] != '\0' && strncmp(buf, tag, strlen(tag)));
112 for (cp = buf; !isspace(*cp); cp++)
117 if (strncmp(cp, "OK", 2) == 0)
123 else if (strncmp(cp, "BAD", 3) == 0)
125 else if (strncmp(cp, "NO", 2) == 0)
127 if (stage == STAGE_GETAUTH)
128 return(PS_AUTHFAIL); /* RFC2060, 6.2.2 */
140 static tSmbNtlmAuthRequest request;
141 static tSmbNtlmAuthChallenge challenge;
142 static tSmbNtlmAuthResponse response;
145 * NTLM support by Grant Edwards.
147 * Handle MS-Exchange NTLM authentication method. This is the same
148 * as the NTLM auth used by Samba for SMB related services. We just
149 * encode the packets in base64 instead of sending them out via a
152 * Much source (ntlm.h, smb*.c smb*.h) was borrowed from Samba.
155 static int do_imap_ntlm(int sock, struct query *ctl)
160 gen_send(sock, "AUTHENTICATE NTLM");
162 if ((result = gen_recv(sock, msgbuf, sizeof msgbuf)))
165 if (msgbuf[0] != '+')
168 buildSmbNtlmAuthRequest(&request,ctl->remotename,NULL);
170 if (outlevel >= O_DEBUG)
171 dumpSmbNtlmAuthRequest(stdout, &request);
173 memset(msgbuf,0,sizeof msgbuf);
174 to64frombits (msgbuf, (unsigned char*)&request, SmbLength(&request));
176 if (outlevel >= O_MONITOR)
177 report(stdout, "IMAP> %s\n", msgbuf);
179 strcat(msgbuf,"\r\n");
180 SockWrite (sock, msgbuf, strlen (msgbuf));
182 if ((gen_recv(sock, msgbuf, sizeof msgbuf)))
185 len = from64tobits ((unsigned char*)&challenge, msgbuf, sizeof(msgbuf));
187 if (outlevel >= O_DEBUG)
188 dumpSmbNtlmAuthChallenge(stdout, &challenge);
190 buildSmbNtlmAuthResponse(&challenge, &response,ctl->remotename,ctl->password);
192 if (outlevel >= O_DEBUG)
193 dumpSmbNtlmAuthResponse(stdout, &response);
195 memset(msgbuf,0,sizeof msgbuf);
196 to64frombits (msgbuf, (unsigned char*)&response, SmbLength(&response));
198 if (outlevel >= O_MONITOR)
199 report(stdout, "IMAP> %s\n", msgbuf);
201 strcat(msgbuf,"\r\n");
202 SockWrite (sock, msgbuf, strlen (msgbuf));
204 if ((result = gen_recv (sock, msgbuf, sizeof msgbuf)))
207 if (strstr (msgbuf, "OK"))
214 static int imap_canonicalize(char *result, char *raw, int maxlen)
215 /* encode an IMAP password as per RFC1730's quoting conventions */
220 for (i = 0; i < strlen(raw) && i < maxlen; i++)
222 if ((raw[i] == '\\') || (raw[i] == '"'))
224 result[j++] = raw[i];
231 static int imap_getauth(int sock, struct query *ctl, char *greeting)
232 /* apply for connection authorization */
236 /* probe to see if we're running IMAP4 and can use RFC822.PEEK */
237 capabilities[0] = '\0';
238 if ((ok = gen_transact(sock, "CAPABILITY")) == PS_SUCCESS)
242 /* capability checks are supposed to be caseblind */
243 for (cp = capabilities; *cp; cp++)
246 /* UW-IMAP server 10.173 notifies in all caps, but RFC2060 says we
247 should expect a response in mixed-case */
248 if (strstr(capabilities, "IMAP4REV1"))
250 imap_version = IMAP4rev1;
251 if (outlevel >= O_DEBUG)
252 report(stdout, GT_("Protocol identified as IMAP4 rev 1\n"));
256 imap_version = IMAP4;
257 if (outlevel >= O_DEBUG)
258 report(stdout, GT_("Protocol identified as IMAP4 rev 0\n"));
261 else if (ok == PS_ERROR)
263 imap_version = IMAP2;
264 if (outlevel >= O_DEBUG)
265 report(stdout, GT_("Protocol identified as IMAP2 or IMAP2BIS\n"));
270 peek_capable = (imap_version >= IMAP4);
273 * Assumption: expunges are cheap, so we want to do them
274 * after every message unless user said otherwise.
276 if (NUM_SPECIFIED(ctl->expunge))
277 expunge_period = NUM_VALUE_OUT(ctl->expunge);
282 * Handle idling. We depend on coming through here on startup
283 * and after each timeout (including timeouts during idles).
285 if (strstr(capabilities, "IDLE") && ctl->idle)
288 if (outlevel >= O_VERBOSE)
289 report(stdout, GT_("will idle after poll\n"));
293 * If either (a) we saw a PREAUTH token in the greeting, or
294 * (b) the user specified ssh preauthentication, then we're done.
296 if (preauth || ctl->server.authenticate == A_SSH)
298 preauth = FALSE; /* reset for the next session */
303 * Time to authenticate the user.
304 * Try the protocol variants that don't require passwords first.
309 if ((ctl->server.authenticate == A_ANY
310 || ctl->server.authenticate == A_GSSAPI)
311 && strstr(capabilities, "AUTH=GSSAPI"))
312 if(ok = do_gssauth(sock, "AUTHENTICATE", ctl->server.truename, ctl->remotename))
314 /* SASL cancellation of authentication */
316 if(ctl->server.authenticate != A_ANY)
324 if ((ctl->server.authenticate == A_ANY
325 || ctl->server.authenticate == A_KERBEROS_V4
326 || ctl->server.authenticate == A_KERBEROS_V5)
327 && strstr(capabilities, "AUTH=KERBEROS_V4"))
329 if ((ok = do_rfc1731(sock, "AUTHENTICATE", ctl->server.truename)))
331 /* SASL cancellation of authentication */
333 if(ctl->server.authenticate != A_ANY)
339 #endif /* KERBEROS_V4 */
342 * No such luck. OK, now try the variants that mask your password
343 * in a challenge-response.
346 if ((ctl->server.authenticate == A_ANY
347 || ctl->server.authenticate == A_CRAM_MD5)
348 && strstr(capabilities, "AUTH=CRAM-MD5"))
350 if ((ok = do_cram_md5 (sock, "AUTHENTICATE", ctl, NULL)))
352 /* SASL cancellation of authentication */
354 if(ctl->server.authenticate != A_ANY)
362 if ((ctl->server.authenticate == A_ANY
363 || ctl->server.authenticate == A_OTP)
364 && strstr(capabilities, "AUTH=X-OTP"))
365 if ((ok = do_otp(sock, "AUTHENTICATE", ctl)))
367 /* SASL cancellation of authentication */
369 if(ctl->server.authenticate != A_ANY)
375 if (ctl->server.authenticate == A_OTP)
378 GT_("Required OTP capability not compiled into fetchmail\n"));
380 #endif /* OPIE_ENABLE */
383 if ((ctl->server.authenticate == A_ANY
384 || ctl->server.authenticate == A_NTLM)
385 && strstr (capabilities, "AUTH=NTLM")) {
386 if ((ok = do_imap_ntlm(sock, ctl)))
388 /* SASL cancellation of authentication */
390 if(ctl->server.authenticate != A_ANY)
397 if (ctl->server.authenticate == A_NTLM)
400 GT_("Required NTLM capability not compiled into fetchmail\n"));
402 #endif /* NTLM_ENABLE */
404 #ifdef __UNUSED__ /* The Cyrus IMAP4rev1 server chokes on this */
405 /* this handles either AUTH=LOGIN or AUTH-LOGIN */
406 if ((imap_version >= IMAP4rev1) && (!strstr(capabilities, "LOGIN")))
409 GT_("Required LOGIN capability not supported by server\n"));
411 #endif /* __UNUSED__ */
413 /* we're stuck with sending the password en clair */
414 if ((ctl->server.authenticate == A_ANY
415 || ctl->server.authenticate == A_PASSWORD)
416 && !strstr (capabilities, "LOGINDISABLED"))
418 /* these sizes guarantee no buffer overflow */
419 char remotename[NAMELEN*2+1], password[PASSWORDLEN*2+1];
421 imap_canonicalize(remotename, ctl->remotename, NAMELEN);
422 imap_canonicalize(password, ctl->password, PASSWORDLEN);
424 strcpy(shroud, ctl->password);
425 ok = gen_transact(sock, "LOGIN \"%s\" \"%s\"", remotename, password);
429 /* SASL cancellation of authentication */
431 if(ctl->server.authenticate != A_ANY)
441 static int internal_expunge(int sock)
442 /* ship an expunge, resetting associated counters */
446 if ((ok = gen_transact(sock, "EXPUNGE")))
449 expunged += deletions;
452 #ifdef IMAP_UID /* not used */
454 #endif /* IMAP_UID */
459 static int imap_idle(int sock)
460 /* start an RFC2177 IDLE */
463 saved_timeout = mytimeout;
466 return (gen_transact(sock, "IDLE"));
469 static int imap_getrange(int sock,
472 int *countp, int *newp, int *bytes)
473 /* get range of messages to be fetched */
476 char buf[MSGBUFSIZE+1], *cp;
478 /* find out how many messages are waiting */
484 * We have to have an expunge here, otherwise the re-poll will
485 * infinite-loop picking up un-expunged messages -- unless the
486 * expunge period is one and we've been nuking each message
487 * just after deletion.
490 if (deletions && expunge_period != 1)
491 ok = internal_expunge(sock);
494 ok = imap_idle(sock);
495 if (ok || gen_transact(sock, "NOOP"))
497 report(stderr, GT_("re-poll failed\n"));
500 else if (count == -1) /* no EXISTS response to NOOP/IDLE */
504 if (outlevel >= O_DEBUG)
505 report(stdout, GT_("%d messages waiting after re-poll\n"), count);
509 ok = gen_transact(sock,
510 check_only ? "EXAMINE \"%s\"" : "SELECT \"%s\"",
511 folder ? folder : "INBOX");
514 report(stderr, GT_("mailbox selection failed\n"));
517 else if (outlevel >= O_DEBUG)
518 report(stdout, GT_("%d messages waiting after first poll\n"), count);
520 /* no messages? then we may need to idle until we get some */
521 if (count == 0 && do_idle)
525 * We should have an expunge here to
526 * a) avoid fetching deleted mails during 'fetchall'
527 * b) getting a wrong count of mails during 'no fetchall'
529 if (!check_only && !ctl->keep && count > 0)
531 ok = internal_expunge(sock);
534 report(stderr, GT_("expunge failed\n"));
537 if (outlevel >= O_DEBUG)
538 report(stdout, GT_("%d messages waiting after expunge\n"), count);
544 /* OK, now get a count of unseen messages and their indices */
545 if (!ctl->fetchall && count > 0)
548 free(unseen_messages);
549 unseen_messages = xmalloc(count * sizeof(unsigned int));
550 memset(unseen_messages, 0, count * sizeof(unsigned int));
553 gen_send(sock, "SEARCH UNSEEN");
555 ok = gen_recv(sock, buf, sizeof(buf));
558 report(stderr, GT_("search for unseen messages failed\n"));
561 else if ((cp = strstr(buf, "* SEARCH")))
565 cp += 8; /* skip "* SEARCH" */
567 while (*cp && unseen < count)
569 /* skip whitespace */
570 while (*cp && isspace(*cp))
575 * Message numbers are between 1 and 2^32 inclusive,
576 * so unsigned int is large enough.
578 unseen_messages[unseen]=(unsigned int)strtol(cp,&ep,10);
580 if (outlevel >= O_DEBUG)
582 GT_("%u is unseen\n"),
583 unseen_messages[unseen]);
591 (tag[0] != '\0' && strncmp(buf, tag, strlen(tag)));
602 static int imap_getsizes(int sock, int count, int *sizes)
603 /* capture the sizes of all messages */
605 char buf [MSGBUFSIZE+1];
608 * Some servers (as in, PMDF5.1-9.1 under OpenVMS 6.1)
609 * won't accept 1:1 as valid set syntax. Some implementors
610 * should be taken out and shot for excessive anality.
612 * Microsoft Exchange (brain-dead piece of crap that it is)
613 * sometimes gets its knickers in a knot about bodiless messages.
614 * You may see responses like this:
616 * fetchmail: IMAP> A0004 FETCH 1:9 RFC822.SIZE
617 * fetchmail: IMAP< * 2 FETCH (RFC822.SIZE 1187)
618 * fetchmail: IMAP< * 3 FETCH (RFC822.SIZE 3954)
619 * fetchmail: IMAP< * 4 FETCH (RFC822.SIZE 1944)
620 * fetchmail: IMAP< * 5 FETCH (RFC822.SIZE 2933)
621 * fetchmail: IMAP< * 6 FETCH (RFC822.SIZE 1854)
622 * fetchmail: IMAP< * 7 FETCH (RFC822.SIZE 34054)
623 * fetchmail: IMAP< * 8 FETCH (RFC822.SIZE 5561)
624 * fetchmail: IMAP< * 9 FETCH (RFC822.SIZE 1101)
625 * fetchmail: IMAP< A0004 NO The requested item could not be found.
627 * This means message 1 has only headers. For kicks and grins
628 * you can telnet in and look:
630 * A003 NO The requested item could not be found.
631 * A004 fetch 1 rfc822.header
632 * A004 NO The requested item could not be found.
634 * * 1 FETCH (BODY ("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 35 3))
635 * A006 OK FETCH completed.
637 * To get around this, we terminate the read loop on a NO and count
638 * on the fact that the sizes array has been preinitialized with a
639 * known-bad size value.
642 gen_send(sock, "FETCH 1 RFC822.SIZE", count);
644 gen_send(sock, "FETCH 1:%d RFC822.SIZE", count);
647 unsigned int num, size;
650 if ((ok = gen_recv(sock, buf, sizeof(buf))))
652 else if (strstr(buf, "OK") || strstr(buf, "NO"))
654 else if (sscanf(buf, "* %u FETCH (RFC822.SIZE %u)", &num, &size) == 2) {
655 if (num > 0 && num <= count)
656 sizes[num - 1] = size;
658 report(stderr, "Warning: ignoring bogus data for message sizes returned by the server.\n");
665 static int imap_is_old(int sock, struct query *ctl, int number)
666 /* is the given message old? */
672 * Expunges change the fetch numbers, but unseen_messages contains
673 * indices from before any expungees were done. So neither the
674 * argument nor the values in message_sequence need to be decremented.
678 for (i = 0; i < unseen; i++)
679 if (unseen_messages[i] == number)
688 static char *skip_token(char *ptr)
690 while(isspace(*ptr)) ptr++;
691 while(!isspace(*ptr) && !iscntrl(*ptr)) ptr++;
692 while(isspace(*ptr)) ptr++;
696 static int imap_fetch_headers(int sock, struct query *ctl,int number,int *lenp)
697 /* request headers of nth message */
699 char buf [MSGBUFSIZE+1];
702 /* expunges change the fetch numbers */
706 * This is blessed by RFC1176, RFC1730, RFC2060.
707 * According to the RFCs, it should *not* set the \Seen flag.
709 gen_send(sock, "FETCH %d RFC822.HEADER", number);
711 /* looking for FETCH response */
717 if ((ok = gen_recv(sock, buf, sizeof(buf))))
719 ptr = skip_token(buf); /* either "* " or "AXXXX " */
720 if (sscanf(ptr, "%d FETCH (%*s {%d}", &num, lenp) == 2)
722 /* try to recover from chronically fucked-up M$ Exchange servers */
723 else if (!strncmp(ptr, "NO", 2))
724 return(PS_TRANSIENT);
725 else if (!strncmp(ptr, "BAD", 3))
726 return(PS_TRANSIENT);
735 static int imap_fetch_body(int sock, struct query *ctl, int number, int *lenp)
736 /* request body of nth message */
738 char buf [MSGBUFSIZE+1], *cp;
741 /* expunges change the fetch numbers */
745 * If we're using IMAP4, we can fetch the message without setting its
746 * seen flag. This is good! It means that if the protocol exchange
747 * craps out during the message, it will still be marked `unseen' on
750 * However...*don't* do this if we're using keep to suppress deletion!
751 * In that case, marking the seen flag is the only way to prevent the
752 * message from being re-fetched on subsequent runs (and according
753 * to RFC2060 p.43 this fetch should set Seen as a side effect).
755 * According to RFC2060, and Mark Crispin the IMAP maintainer,
756 * FETCH %d BODY[TEXT] and RFC822.TEXT are "functionally
757 * equivalent". However, we know of at least one server that
758 * treats them differently in the presence of MIME attachments;
759 * the latter form downloads the attachment, the former does not.
760 * The server is InterChange, and the fool who implemented this
761 * misfeature ought to be strung up by his thumbs.
763 * When I tried working around this by disabling use of the 4rev1 form,
764 * I found that doing this breaks operation with M$ Exchange.
765 * Annoyingly enough, Exchange's refusal to cope is technically legal
766 * under RFC2062. Trust Microsoft, the Great Enemy of interoperability
767 * standards, to find a way to make standards compliance irritating....
769 switch (imap_version)
771 case IMAP4rev1: /* RFC 2060 */
773 gen_send(sock, "FETCH %d BODY.PEEK[TEXT]", number);
775 gen_send(sock, "FETCH %d BODY[TEXT]", number);
778 case IMAP4: /* RFC 1730 */
780 gen_send(sock, "FETCH %d RFC822.TEXT.PEEK", number);
782 gen_send(sock, "FETCH %d RFC822.TEXT", number);
785 default: /* RFC 1176 */
786 gen_send(sock, "FETCH %d RFC822.TEXT", number);
790 /* looking for FETCH response */
794 if ((ok = gen_recv(sock, buf, sizeof(buf))))
797 (!strstr(buf+4, "FETCH") || sscanf(buf+2, "%d", &num) != 1);
803 * Try to extract a length from the FETCH response. RFC2060 requires
804 * it to be present, but at least one IMAP server (Novell GroupWise)
807 if ((cp = strchr(buf, '{')))
808 *lenp = atoi(cp + 1);
810 *lenp = -1; /* missing length part in FETCH reponse */
815 static int imap_trail(int sock, struct query *ctl, int number)
816 /* discard tail of FETCH response after reading message text */
818 /* expunges change the fetch numbers */
819 /* number -= expunged; */
823 char buf[MSGBUFSIZE+1];
826 if ((ok = gen_recv(sock, buf, sizeof(buf))))
829 /* UW IMAP returns "OK FETCH", Cyrus returns "OK Completed" */
830 if (strstr(buf, "OK"))
835 * Any IMAP server that fails to set Seen on a BODY[TEXT]
836 * fetch violates RFC2060 p.43 (top). This becomes an issue
837 * when keep is on, because seen messages aren't deleted and
838 * get refetched on each poll. As a workaround, if keep is on
839 * we can set the Seen flag explicitly.
841 * This code isn't used yet because we don't know of any IMAP
842 * servers broken in this way.
845 if ((ok = gen_transact(sock,
846 imap_version == IMAP4
847 ? "STORE %d +FLAGS.SILENT (\\Seen)"
848 : "STORE %d +FLAGS (\\Seen)",
851 #endif /* __UNUSED__ */
857 static int imap_delete(int sock, struct query *ctl, int number)
858 /* set delete flag for given message */
862 /* expunges change the fetch numbers */
866 * Use SILENT if possible as a minor throughput optimization.
867 * Note: this has been dropped from IMAP4rev1.
869 * We set Seen because there are some IMAP servers (notably HP
870 * OpenMail) that do message-receipt DSNs, but only when the seen
871 * bit is set. This is the appropriate time -- we get here right
872 * after the local SMTP response that says delivery was
875 if ((ok = gen_transact(sock,
876 imap_version == IMAP4
877 ? "STORE %d +FLAGS.SILENT (\\Seen \\Deleted)"
878 : "STORE %d +FLAGS (\\Seen \\Deleted)",
885 * We do an expunge after expunge_period messages, rather than
886 * just before quit, so that a line hit during a long session
887 * won't result in lots of messages being fetched again during
890 if (NUM_NONZERO(expunge_period) && (deletions % expunge_period) == 0)
891 internal_expunge(sock);
896 static int imap_logout(int sock, struct query *ctl)
897 /* send logout command */
899 /* if any un-expunged deletions remain, ship an expunge now */
901 internal_expunge(sock);
904 /* Memory clean-up */
906 free(unseen_messages);
907 #endif /* USE_SEARCH */
909 return(gen_transact(sock, "LOGOUT"));
912 const static struct method imap =
914 "IMAP", /* Internet Message Access Protocol */
918 #else /* INET6_ENABLE */
919 143, /* standard IMAP2bis/IMAP4 port */
920 993, /* ssl IMAP2bis/IMAP4 port */
921 #endif /* INET6_ENABLE */
922 TRUE, /* this is a tagged protocol */
923 FALSE, /* no message delimiter */
924 imap_ok, /* parse command response */
925 imap_getauth, /* get authorization */
926 imap_getrange, /* query range of messages */
927 imap_getsizes, /* get sizes of messages (used for ESMTP SIZE option) */
928 imap_is_old, /* no UID check */
929 imap_fetch_headers, /* request given message headers */
930 imap_fetch_body, /* request given message body */
931 imap_trail, /* eat message trailer */
932 imap_delete, /* delete the message */
933 imap_logout, /* expunge and exit */
934 TRUE, /* yes, we can re-poll */
937 int doIMAP(struct query *ctl)
938 /* retrieve messages using IMAP Version 2bis or Version 4 */
940 return(do_protocol(ctl, &imap));
943 /* imap.c ends here */